/*
Let S(n,k,b) represent the number of valid solutions to x1 + x2 + ... + xk ≤ n, where 0 ≤ xm ≤ bm for all 1 ≤ m ≤ k.

For example, S(14,3,2) = 135, S(200,5,3) = 12949440, and S(1000,10,5) mod 1 000 000 007 = 624839075.

Find (∑10 ≤ k ≤ 15 S(10k,k,k)) mod 1 000 000 007.

Anser:
Time:
*/
package main

import (
	"fmt"
	"time"
)

func main() {
	tstart := time.Now()



	tend := time.Now()
	fmt.Println(tend.Sub(tstart))
}